Process for reducing the chlorine content of organomonophosphites using two solutions

ABSTRACT

Process with universal usefulness for reducing the chlorine content of organomonophosphites, using two solutions.

The invention relates to a process with universal usefulness forreducing the chlorine content of organomonophosphites, using twosolutions.

Organophosphorus compounds have gained considerable industrialsignificance because of their wide range of use. They are used directlyas plasticizers, flame retardants, UV stabilizers or as antioxidants. Inaddition, they are important intermediates in the production offungicides, herbicides, insecticides and pharmaceuticals.

A specific field of use of the organophosphorus compounds is catalysis:

For instance, especially phosphines, phosphites and phosphoramidites areused as ligands in catalyst complexes, which are used in turn for thehomogeneous catalysis of processes operated on an industrial scale.Particular mention should be made of the hydroformylation of unsaturatedcompounds with carbon monoxide and hydrogen, which generally takes placein the presence of a homogeneous catalyst system which has a metal andat least one organophosphorus compound as ligand.

An introduction to homogeneously catalyzed hydroformylation is given in:B. CORNILS, W. A. HERRMANN: Applied Homogeneous Catalysis withOrganometallic Compounds. Vol. 1 & 2, VCH, Weinheim, N.Y., 1996; R.Franke, D. Selent, A. Börner: Applied Hydroformylation. Chem. Rev.,2012, DOI:10.1021/cr3001803.

The synthesis of phosphorous ligands is described repeatedly in theliterature. A good overview can be found in “Phosphorous(III) Ligands inHomogeneous Catalysis—Design and Synthesis” by Paul C. J. Kamer and PietW. N. M. van Leeuwen; John Wiley and Sons, 2012.

In the synthesis of these ligands, chlorine-containing reagents arefrequently used. For instance, in the synthesis of phosphite ligands,phosphorus trichloride (PCl₃) is usually used.

The chlorine compounds used in the preparation of organophosphoruscompounds present many difficulties in the proper use or furtherprocessing of the organophosphorus compound:

For instance, the desired organophosphorus compound is never obtained inpure form immediately, and is always obtained in contaminated form as anorganophosphorus product which, as well as the desired organophosphoruscompound, also contains contaminants. The contaminants are unconvertedor incompletely converted reagents, auxiliaries or products from sidereactions. In this context, contaminants in the form of chlorinecompounds present particular difficulties:

If the chlorine-containing contaminants get into a steel pressurereactor together with the organophosphorus compound used as ligand, thepressure reactor is subject to increased corrosion as a result of thechloride. This is especially true of continuous processes, in which theorganophosphorus compounds are metered in over the course of thereaction. This is the case, for example, when the organophosphoruscompound is used as a ligand in industrial scale hydroformylation. Themetered addition inevitably also results in an accumulation of thesecondary components in the reactor. This is critical especially whenchloride is one of the secondary components, since chloride attacks evenstainless steels (cf. Merkblatt 893 “Edelstahl rostfrei für dieWasserwirtschaft” [Information Sheet 893 “Corrosion-Free Stainless Steelfor Water Management”], 1st edition 2007, publisher: InformationsstelleEdelstahl Rostfrei, Düsseldorf.)

One important class of organophosphorus compounds is that of theorganomonophosphites, or monophosphites for short.

In hydroformylation, these compounds play a prominent part (see R.Franke, D. Selent, A. Börner: Applied Hydroformylation. Chem. Rev.,2012, DOI:10.1021/cr3001803).

The chloride content can be determined analytically in a simple manner,for example by aqueous titration. A more extensive determination is thatof the total chlorine content, which, as well as the chlorides, alsoencompasses chlorine bound in other forms. Emphasis on the totalchlorine content is also of material relevance, in that it cannot beruled out that chlorine bound in other forms is also able to damage thereactor. In judging the limits for total chlorine, however, the chloridefraction remains crucial.

The patent literature discloses various methods for reducing the totalchlorine content of organophosphorus ligands after the actual synthesis.

WO 2013/098368 A1 describes the purification of organodiphosphites, inwhich the impurities for removal include not only chloride ions butalso, in particular, diols, basic impurities, mono- and dioxides, andalso secondary organophosphites. Because of the differences instructural composition and the associated differences in chemical andphysical properties such as solubilities between monophosphites anddiphosphites, the purification process described in this earlierspecification cannot be transposed to the purification oforganomonophosphites.

DE 10 2011 002 640 A1 discloses a process for purifying biphephos, abisphosphite,(6,6′-[(3,3′-di-tert-butyl-5,5′-dimethoxy-1,1′-biphenyl-2,2′-diyl)bis(oxy)]bis(dibenzo[d,f][1,3,2]dioxaphosphepine)).The process described therein is intended to reduce the chlorine contentof biphephos. This is done by washing the biphephos with a solventselected from ethyl acetate, anisole, ortho-xylene, toluene, acetone,2-propanol and C₅-C₁₀-alkanes, or recrystallizing from such a solvent.In this context, however, the long period needed to precipitate orcrystallize the product is in need of improvement. The ligand isprecipitated overnight, meaning that >8 hours are required. Moreover, itis pointed out in the examples that another solvent has to be addedafter the precipitation overnight, in order to complement theprecipitation (example 2 of DE 10 2011 002 640 A1). These long reactiontimes are problematic in industrial scale syntheses, since the effect oflong residence times and hence ultimately long production times for theligand is to increase the cost thereof.

Document EP 0 285 136 claims a process for purifying tertiaryorganophosphites of pentavalent organophosphorus compounds which form asby-products of the synthesis and also as degradation or hydrolysisproducts of the tertiary organophosphites. The process envisages thetreatment of the dissolved contaminated organophosphite with water atelevated temperature in the presence of a Lewis base. Lewis bases usedare inorganic salts (carbonates, hydroxides, oxides), tertiary aminesand polymers which carry amine groups. One disadvantage of the processdescribed in EP 0 285 136 lies in the treatment with water. Not only theimpurities to be removed but also the tertiary organophosphitesthemselves react under the conditions specified, such that a portion ofthe product of value is lost according to the hydrolysis stability ofthe organophosphites. This is particularly critical here, since washingtakes place with water; that is, high concentrations are used.

Document DE 10 2004 049 339 describes a process for purifyingphosphorous chelate ligands by means of extraction using a polarextractant. The crude ligand was extracted here six times with a polarsolvent, and then has a content of amine base, amine hydrochloride ormixtures thereof of less than 100 ppm. In this method of purification,however, enormous amounts of solvent are needed, which is in need ofimprovement from an economic and ecological point of view.

It was thus an object of the present invention to develop a purifyingprocess for organomonophosphites, in which the chlorine content isreduced, without this process having the above-described disadvantages.

A particular object was for the process to purify organomonophosphiteshaving a chlorine content of more than 1000 ppm to 100 000 ppm and moreparticularly of 5000 ppm to 100 000 ppm in the organomonophosphite to achlorine content of less than 1000 ppm in the organomonophosphite.Preferably, the chlorine content was to be reduced to less than 500 ppmin the organomonophosphite, and more preferably to less than 200 ppm inthe organomonophosphite. The chlorine contents reported are meant astotal chlorine contents.

The total chlorine content is determined by the Wickbold method: Samplepreparation according to DIN 51408, and measurement by ionchromatography according to DIN EN ISO 10304.

The contaminated organomonophosphite can contain organic chloridesand/or inorganic chlorides. Organic chlorides contain at least onecarbon atom, whereas inorganic chlorides do not include any carbon.Contamination of the organophosphorus product by the following chloridesis particularly likely, since these chlorine-containing compounds areeither required in the course of synthesis of organophosphorus compoundsor are unavoidably produced as by-products: phosphorus trichloride,chlorophosphites, dichlorophosphites, hydrochlorides of amines,hydrochlorides of alkali metals, chlorides of alkaline earth metals,chlorine-containing acids obtainable from the hydrolysis of phosphorustrichloride. Therefore, the contaminated organomonophosphite generallyincludes at least one of the chlorides enumerated.

This object is achieved by a process according to claim 1.

A process for reducing the chlorine content in an organomonophosphite ofone of the general formulae I, II, III, IV, V, VI, VII, VIII, IX and X:

where the radicals R¹, R², R³, R⁴, R⁵, R⁶, R⁷, R⁸, R²¹, R²², R²³, R²⁴,R²⁵, R³¹, R³², R³³, R³⁴, R³⁵, R⁴¹, R⁴², R⁴³, R⁴⁴, R⁴⁵ are selected eachindependently from:—H, —(C₁-C₁₂)-alkyl, —O—(C₁-C₁₂)-alkyl, —O—(C₆-C₂₀)-aryl,—(C₆-C₂₀)-aryl;and R¹⁰ is —(C₁-C₁₂)-alkyl.and T is selected from:—CH₃, —CF₃, —CH₂C₆H₅;and Q is selected from:—(C₁-C₁₂)-alkyl-, —C(CH₃)₃;and V is selected from:—CH₂CH₂COCH₃, —C(CH₃)₃, —C₆H₅;and W is selected from:-Me, —CH₂CH₃, —CH₂CH₂CH₃, —CH₂-cyclo-C₃H₅, —CH(CH₃)₂, -cyclo-C₆H₁₁,—C(CH₃)₃, —CH₂C₆H₅, —CH₂C₆H₃-2,4-(CH₃)₂;and X and Y are each independently selected from:—(C₁-C₁₂)-alkyl, —(C₆-C₂₀)-aryl, —(C₆-C₂₀)-aryl-(C₁-C₁₂)-alkyl,—(C₁-C₁₂)-alkyl-O—(C₆-C₂₀)-aryl.and Z is selected from:—(C₁-C₁₂)-alkyl-, —(C₆-C₂₀)-aryl-, —(C₆-C₂₀)-aryl-(C₆-C₂₀)-aryl-;and the alkyl, cycloalkyl, and aryl groups mentioned may be substituted;comprising the process steps of:a) partly or fully dissolving the organomonophosphite in a firstsolution comprising a first solvent selected from aromatics, alcohols,acetone, ethyl acetate, acetonitrile and ether;b) introducing the first solution into a second solution comprising asecond solvent selected from aromatics, C₅-C₁₀-alkanes, alcohols,acetone, ethyl acetate, acetonitrile, ether, water, where at least oneof the two solutions comprises dimethylaminobutane or triethylamine ortriethanolamine;c) precipitating the purified organomonophosphite.

In one preferred variant of the process, at least one of the twosolutions comprises dimethylaminobutane.

The dimethylaminobutane, triethylamine and/or triethanolamine suppressunwanted side reactions which would take place, for example, in thepresence of water or alcohols as solvents, such an alcoholysis or atransesterification, for example. Another advantage is that the boundchlorine originally present in the monophosphite dissolves moreeffectively in the solution by virtue of the dimethylaminobutane presentin the solution.

(C₁-C₁₂)-Alkyl and O—(C₁-C₁₂)-alkyl may each be unsubstituted orsubstituted by one or more identical or different radicals selected from(C₃-C₁₂)-cycloalkyl, (C₃-C₁₂)-heterocycloalkyl, (C₆-C₂₀)-aryl, fluorine,chlorine, cyano, formyl, acyl and alkoxycarbonyl.

(C₃-C₁₂)-Cycloalkyl and (C₃-C₁₂)-heterocycloalkyl may each beunsubstituted or substituted by one or more identical or differentradicals selected from (C₁-C₁₂)-alkyl, (C₁-C₁₂)-alkoxy,(C₃-C₁₂)-cycloalkyl, (C₃-C₁₂)-heterocycloalkyl, (C₆-C₂₀)-aryl, fluorine,chlorine, cyano, formyl, acyl and alkoxycarbonyl.

(C₆-C₂₀)-Aryl may each be unsubstituted or substituted by one or moreidentical or different radicals selected from (C₁-C₁₂)-alkyl,(C₁-C₁₂)-alkoxy, (C₃-C₁₂)-cycloalkyl, (C₃-C₁₂)-heterocycloalkyl,(C₆-C₂₀)-aryl, fluorine, chlorine, cyano, formyl, acyl andalkoxycarbonyl.

In the context of the invention, the expression “—(C₁-C₁₂)-alkyl”encompasses straight-chain and branched alkyl groups. Preferably, thesegroups are unsubstituted straight-chain or branched —(C₁-C₈)-alkylgroups and most preferably —(C₁-C₆)-alkyl groups. Examples of—(C₁-C₁₂)-alkyl groups are especially methyl, ethyl, propyl, isopropyl,n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, 2-pentyl,2-methylbutyl-, 3-methylbutyl-, 1,2-dimethylpropyl-, 1,1-dimethylpropyl,2,2-dimethylpropyl-, 1-ethylpropyl-, n-hexyl-, 2-hexyl-,2-methylpentyl-, 3-methylpentyl-, 4-methylpentyl-, 1,1-dimethylbutyl-,1,2-dimethylbutyl-, 2,2-dimethylbutyl-, 1,3-dimethylbutyl-,2,3-dimethylbutyl-, 3,3-dimethylbutyl-, 1,1,2-trimethylpropyl-,1,2,2-trimethylpropyl-, 1-ethylbutyl-, 1-ethyl-2-methylpropyl-,n-heptyl-, 2-heptyl-, 3-heptyl-, 2-ethylpentyl-, 1-propylbutyl-,n-octyl-, 2-ethylhexyl-, 2-propylheptyl-, nonyl-, decyl.

The elucidations relating to the expression “—(C₁-C₁₂)-alkyl” also applyto the alkyl groups in —O—(C₁-C₁₂)-alkyl, i.e. in —(C₁-C₁₂)-alkoxy.Preferably, these groups are unsubstituted straight-chain or branched—(C₁-C₆)-alkoxy groups.

Substituted —(C₁-C₁₂)-alkyl groups and substituted —(C₁-C₁₂)-alkoxygroups may have one or more substituents, depending on their chainlength. The substituents are preferably each independently selected from—(C₃-C₁₂)-cycloalkyl, —(C₃-C₁₂)-heterocycloalkyl, —(C₆-C₂₀)-aryl,fluorine, chlorine, cyano, formyl, acyl and alkoxycarbonyl.

The expression “—(C₃-C₁₂)-cycloalkyl”, in the context of the presentinvention, encompasses mono-, bi- or tricyclic hydrocarbyl radicalshaving 3 to 12, especially 5 to 12, carbon atoms. These includecyclopropyl-, cyclobutyl-, cyclopentyl-, cyclohexyl-, cycloheptyl-,cyclooctyl-, cyclododecyl-, cyclopentadecyl-, norbonyl- and adamantyl.

The expression “—(C₃-C₁₂)-heterocycloalkyl groups”, in the context ofthe present invention, encompasses nonaromatic saturated or partlyunsaturated cycloaliphatic groups having 3 to 12, especially 5 to 12,carbon atoms. The —(C₃-C₁₂)-heterocycloalkyl groups have preferably 3 to8, more preferably 5 or 6, ring atoms. In the heterocycloalkyl groups,as opposed to the cycloalkyl groups, 1, 2, 3 or 4 of the ring carbonatoms are replaced by heteroatoms or heteroatom-containing groups. Theheteroatoms or the heteroatom-containing groups are preferably selectedfrom —O—, —S—, —N—, —N(═O)—, —C(═O)— and —S(═O)—. Examples of—(C₃-C₁₂)-heterocycloalkyl groups are tetrahydrothiophenyl,tetrahydrofuryl, tetra hydropyranyl and dioxanyl.

Substituted —(C₃-C₁₂)-cycloalkyl groups and substituted—(C₃-C₁₂)-heterocycloalkyl groups may have one or more (e.g. 1, 2, 3, 4or 5) further substituents, depending on their ring size. Thesesubstituents are preferably each independently selected from—(C₁-C₁₂)-alkyl, —(C₁-C₁₂)-alkoxy, —(C₃-C₁₂)-cycloalkyl,—(C₃-C₁₂)-heterocycloalkyl, —(C₆-C₂₀)-aryl, fluorine, chlorine, cyano,formyl, acyl and alkoxycarbonyl. Substituted —(C₃-C₁₂)-cycloalkyl groupspreferably bear one or more —(C₁-C₆)-alkyl groups. Substituted—(C₃-C₁₂)-heterocycloalkyl groups preferably bear one or more—(C₁-C₆)-alkyl groups.

In the context of the present invention, the expression “—(C₆-C₂₀)-aryl”encompasses mono- or polycyclic aromatic hydrocarbyl radicals. Thesehave 6 to 20 ring atoms, more preferably 6 to 14 ring atoms, especially6 to 10 ring atoms. Aryl is preferably —(C₆-C₁₀)-aryl. Aryl isespecially phenyl, naphthyl, indenyl, fluorenyl, anthracenyl,phenanthrenyl, naphthacenyl, chrysenyl, pyrenyl, coronenyl. Moreparticularly, aryl is phenyl, naphthyl and anthracenyl.

Substituted —(C₆-C₂₀)-aryl groups may have one or more (e.g. 1, 2, 3, 4or 5) substituents, depending on the ring size. These substituents arepreferably each independently selected from —(C₁-C₁₂)-alkoxy,—(C₃-C₁₂)-cycloalkyl, —(C₃-C₁₂)-heterocycloalkyl, —(C₆-C₂₀)-aryl,fluorine, chlorine, cyano, formyl, acyl and alkoxycarbonyl.

Substituted —(C₆-C₂₀)-aryl groups are preferably substituted—(C₆-C₁₀)-aryl groups, especially substituted phenyl or substitutednaphthyl or substituted anthracenyl. Substituted —(C₆-C₂₀)-aryl groupspreferably bear one or more, for example 1, 2, 3, 4 or 5, substituentsselected from —(C₁-C₁₂)-alkyl groups, —(C₁-C₁₂)-alkoxy groups.

In one variant of the process, the first solvent is selected from: ethylacetate, anisole, ortho-xylene, toluene. acetone, methanol, ethanol,propanol, isopropanol, acetonitrile.

Preferably, the first solvent is selected from: ethyl acetate, anisole,ortho-xylene, toluene.

More preferably, the first solvent is toluene.

In one variant of the process, the second solvent is selected from:

ethyl acetate, anisole, ortho-xylene, toluene, acetone, methanol,ethanol, propanol, isopropanol, acetonitrile, tetrahydrofuran, diethylether, glycol, C₅-C₁₀-alkanes.

Preferably, the second solvent is selected from: ethyl acetate, acetone,methanol, ethanol, propanol, isopropanol, acetonitrile, C₅-C₁₀-alkanes.

More preferably, the second solvent is acetonitrile or methanol orethanol.

More preferably, the second solvent is acetonitrile or methanol.

In one variant of the process, the second solution comprises a thirdsolvent.

In one variant of the process, the third solvent is water.

In one variant of the process, the first solution comprisesdimethylaminobutane.

In one variant of the process, the second solution comprisesdimethylaminobutane.

In one variant of the process, the first solution comprisestriethanolamine.

In one variant of the process, the second solution comprisestriethanolamine.

In one variant of the process, the first and second solutions comprisedimethylaminobutane.

In one variant of the process, the first and second solutions comprisetriethanolamine.

In one variant of the process, in process step a), theorganomonophosphite is dissolved fully in the first solution.

In one variant of the process, the introduction in process step b) iseffected by means of dropwise addition.

In another variant of the process, the introduction in process step b)is effected by means of metered addition.

In a preferred embodiment of the process according to the invention, theorganomonophosphite is dissolved in the first solvent, preferably whileheating, insoluble constituents are removed by filtration (by what iscalled a clarifying filtration, optionally also with addition of afiltering aid), preferably at a temperature of up to 130° C., and theorganomonophosphite is subsequently metered into the second solventwhile warm, such that the organomonophosphite precipitates out orcrystallizes out. The degree of precipitation of the organomonophosphiteis optionally increased by a reduction in temperature, to a temperature,for example, of −20 to +10° C., more particularly to about 0° C.

Filtration aids used may be either mineral filtration aids, for examplesilicon dioxide, or organic filtration aids, for example cellulose oractivated carbon. It is also possible to mix different filtration aids.

In one variant of the process, the purified organomonophosphite has achlorine content of <1000 ppm.

In one variant of the process, the purified organomonophosphite has achlorine content of <200 ppm.

In one variant of the process, the organomonophosphite has a chlorinecontent of 1500 ppm to 100 000 ppm on introduction in process step b).

Preferably, the organomonophosphite has a chlorine content of 5000 ppmto 100 000 ppm on introduction in process step b).

The chlorine contents reported are meant as total chlorine contents.

The total chlorine content is determined by the Wickbold method: samplepreparation according to DIN 51408 and measurement by ion chromatographyaccording to DIN EN ISO 10304.

In one variant of the process, the second solution is heated to atemperature in the range from −20° C. to 120° C. before the firstsolution is introduced into the second solution in process step b).

The temperature of the solvent should be chosen here such that it doesnot boil. The temperature thus depends on the choice of solvent.

Preferably, the second solution is brought to a temperature in the rangefrom −10° C. to 80° C. before the first solution is introduced into thesecond solution in process step b).

In one variant of the process, the organomonophosphite has one of thegeneral formulae I, II, III and IV:

In one variant of the process, R¹, R², R³, R⁴, R⁵, R⁶, R⁷, R⁸ are eachindependently selected from: —H, —(C₁-C₁₂)-alkyl, —O—(C₁-C₁₂)-alkyl,—O—(C₆-C₂₀)-aryl, —(C₆-C₂₀)-aryl.

and W is —CH₃;

and Q is —C(CH₃)₃.

In one variant of the process, Z is:

In one variant of the process, Z is:

where R¹¹, R¹², R¹³, R¹⁴, R¹⁵, R¹⁶, R¹⁷, R¹⁸ are each independentlyselected from: —H, —(C₁-C₁₂)-alkyl, —O—(C₁-C₁₂)-alkyl, —O—(C₆-C₂₀)-aryl,—(C₆-C₂₀)-aryl, -halogen (such as Cl, F, Br, I), —COO—(C₁-C₁₂)-alkyl,—CONH—(C₁-C₁₂)-alkyl, —(C₆-C₂₀)-aryl-CON[(C₁-C₁₂)-alkyl]₂,—CO—(C₁-C₁₂)-alkyl, —CO—(C₆-C₂₀)-aryl, —COOH, —OH, —SO₃H, —SO₃Na, —NO₂,—CN, —NH₂, —N[(C₁-C₁₂)-alkyl]₂.

In one variant of the process, the radicals R¹¹, R¹², R¹³, R¹⁴, R¹⁵,R¹⁶, R¹⁷, R¹⁸ are each independently selected from:

—H, —(C₁-C₁₂)-alkyl, —O—(C₁-C₁₂)-alkyl, —O—(C₆-C₂₀)-aryl,—(C₆-C₂₀)-aryl, -halogen (such as Cl, F, Br, I).

In one variant of the process, the radicals R¹¹, R¹², R¹³, R¹⁴, R¹⁵,R¹⁶, R¹⁷, R¹⁸ are each independently selected from:

—H, —(C₁-C₁₂)-alkyl, —O—(C₁-C₁₂)-alkyl.

The process of the invention serves with particular preference for thepurification of monophosphites of one of the structural formulae XI,XII, XIII, XIV, XV and XVI:

The process claimed may also have upstream process steps, for examplethe synthesis of the ligands. In that case, these process steps areeffected prior to process step a).

Where the ligand is synthesized upstream of process step a), theorganomonophosphite may be isolated after crystallization has takenplace. This is typically accomplished by filtering off and, optionally,drying the filtered-off organomonophosphite.

A particular advantage is that certain solvent combinations which resultfrom the ligand synthesis (acetonitrile (ACN), N,N′-dimethylaminobutane(DMAB) or triethylamine (NEt₃) or triethanolamine) can be used forrecystallization after a single distillation.

This allows reuse of the mixture used from the synthesis, which isadvantageous from an ecological and economic point of view. Furthermore,it is also possible to dispense with the addition of a filtration aid.

This is therefore a particularly simple and efficient process. In thiscontext, it is also particularly advantageous that this process isperformable very rapidly, meaning that the purified organomonophosphiteprecipitates out or crystallizes out again after a short reaction time,and the process thus has good space-time yields. This is advantageousespecially for a synthesis on the industrial scale, since prolongedreaction times directly affect the cost of the compound. The goodpossibility of industrial scale use is an important criterion, since thepreparation complexity and the associated costs that arise may only beso high that the viability of the overall process is still assured.

As well as the process, the use of the product obtained by this processin a hydroformylation reaction is also claimed. The product herefunctions as a ligand in a catalyst complex composed of the ligand andat least one central metal atom or ion. This catalyst complex is usedfor catalysis of a hydroformylation reaction.

The use of an organomonophosphite of one of the general formulae I, II,III, IV, V, VI, VII, VIII, IX and X which has been purified by anabove-described method as a ligand in a catalyst complex which catalyzesa hydroformylation reaction.

The invention is to be illustrated in detail hereinafter by workingexamples.

GENERAL OPERATING PROCEDURES

The total chlorine content reported in connection with this invention isdetermined according to Wickbold: Sample preparation according to DIN51408 and measurement by ion chromatography according to DIN EN ISO10304.

All the preparations which follow were conducted with standard Schlenkvessel technology under protective gas. The solvents were dried oversuitable desiccants before use (Purification of Laboratory Chemicals, W.L. F. Armarego (Author), Christina Chai (Author), Butterworth Heinemann(Elsevier), 6th edition, Oxford 2009).

The products were characterized by means of NMR spectroscopy. Chemicalshifts are reported in ppm.

The ³¹P NMR signals were referenced according to:SR_(31P)═SR_(1H)*(BF_(31P)/BF_(1H))═SR_(1H)*0.4048. (Robin K. Harris,Edwin D. Becker, Sonia M. Cabral de Menezes, Robin Goodfellow, andPierre Granger, Pure Appl. Chem., 2001, 73, 1795-1818; Robin K. Harris,Edwin D. Becker, Sonia M. Cabral de Menezes, Pierre Granger, Roy E.Hoffman and Kurt W. Zilm, Pure Appl. Chem., 2008, 80, 59-84). Thechlorine determination was effected in the form of combustion accordingto Wickbold; with sample preparation to DIN 51408 and analysis by ionchromatography to DIN EN ISO 10304.

Example 1: Synthesis of (XI) Reaction Scheme

Introduction of the BOC Group:

In a 2 l Schlenk flask, 400 mmol (143.8 g) of3,3′-di-tert-butyl-5,5-dimethoxy-[1,1′-biphenyl]-2,2′-diol and 40 mmol(4.8 g) of N,N-dimethylaminopyridine (DMAP) were dissolved in 900 ml ofCH₂Cl₂. Subsequently, at room temperature, 400 mmol (88 g) ofdi-tert-butyl dicarbonate were dissolved in 280 ml of CH₂Cl₂,transferred to a 500 ml dropping funnel and added dropwise to thebiphenol/DMAP solution at 32° C. within one hour. The solution wasstirred at room temperature overnight. The next morning, the solvent wasremoved under reduced pressure. The slightly waxy, reddish residue wasadmixed with 800 ml of n-heptane and stirred overnight. This gave awhite residue which was filtered off, washed twice with 50 ml ofn-heptane and then dried. The target product was obtained as a whitesolid (161.6 g, 84%). ¹H NMR (toluene-d₈): 95% and further impurities.

Reaction of tert-butyl(3,3′-di-tert-butyl-2′-hydroxy-5,5′-dimethoxy-[1,1′-biphenyl]-2-yl)carbonatewith Phosphorus Trichloride

In a 250 ml Schlenk flask which had been repeatedly evacuated and filledwith inert gas, 12 g (0.026 mol) of tert-butyl(3,3′-di-tert-butyl-2′-hydroxy-5,5-dimethoxy-[1,1′-biphenyl]-2-yl)carbonatewere dissolved by stirring in 120 ml of dried toluene and 12.8 ml (0.091mol) of triethylamine.

In a second 500 ml Schlenk flask, 100 ml of dried toluene were firststirred together with 8.1 ml (0.091 mol) of phosphorus trichloride.Subsequently, the phosphorus trichloride-toluene solution was addeddropwise to the previously prepared carbonate-amine-toluene solution atroom temperature within 30 minutes. On completion of addition, themixture was heated to 80° C. for 30 minutes and cooled to RT overnight.

The next morning, the mixture was filtered, the solids were washed with50 ml of dried toluene, and the filtrate was concentrated to dryness.The target product was obtained as a solid (13.1 g, 89%). ³¹P NMR (202.4MHz, toluene-d₈): 203.2 and 203.3 ppm (100%).

Reaction of tert-butyl(3,3′-di-tert-butyl-2′-((dichlorophosphino)oxy)-5,5′-dimethoxy-[1,1′-biphenyl]-2-yl)carbonatewith 3,3′,5,5′-tetramethyl-(1,1′-biphenyl)-2,2′-diol

In a 1 l Schlenk flask which had been repeatedly evacuated and filledwith inert gas, 24.7 g (0.044 mol) of tert-butyl(3,3′-di-tert-butyl-2′-((dichlorophosphino)oxy)-5,5′-dimethoxy-[1,1′-biphenyl]-2-yl)carbonatewere dissolved in 400 ml of acetonitrile.

In a second Schlenk flask (1 l) which had been repeatedly evacuated andfilled with inert gas, 10.8 g (0.044 mol) of3,3′,5,5′-tetramethyl-(1,1-biphenyl)-2,2′-diol were dissolved bystirring in 200 ml of acetonitrile and 13.1 ml (0.011 mol) of driedtriethylamine. Subsequently, the chlorophosphite solution was slowlyadded dropwise to the biphenol-triethylamine solution and the mixturewas stirred overnight.

The mixture was then filtered and the residue was washed twice with 15ml of acetonitrile.

The filtrate was concentrated under reduced pressure until a solidprecipitated out. The latter was filtered and dried. The target product(XI) was obtained as a white solid (28.5 g, 87%). ³¹P NMR (202.4 MHz,toluene-d₈): 139.4 ppm (98.5%).

Example 2: Synthesis of (XII) Reaction of tert-butyl(3,3′-di-tert-butyl-2′-hydroxy-5,5′-dimethoxy-[1,1′-biphenyl]-2-yl)carbonatewith 2-chloro-4,4,5,5-tetraphenyl-1,3,2-dioxaphospholane

In a 250 ml Schlenk flask which had been repeatedly evacuated and filledwith inert gas, 9.1 g (0.021 mol) of2-chloro-4,4,5,5-tetraphenyl-1,3,2-dioxaphospholane were dissolved in 75ml of dried toluene.

In a second Schlenk flask (250 ml), 9.2 g (0.02 mol) of tert-butyl(3,3′-di-tert-butyl-2′-hydroxy-5,5′-dimethoxy-[1,1-biphenyl]-2-yl)carbonateand 2.3 g (0.02 mol) of potassium tert-butoxide were dissolved in 75 mlof dried toluene while stirring.

Subsequently, the carbonate/potassium tert-butoxide/toluene mixture wasslowly added dropwise at room temperature to the chlorophosphitesolution, and the mixture was stirred at room temperature overnight.

Thereafter, the solvent was removed under reduced pressure. Theresultant residue was stirred in 75 ml of dried acetonitrile for 5hours. The solids were filtered, washed with dried acetonitrile anddried. The target product (XII) was obtained as a white solid (15.3 g,90%). ³¹P NMR (202.4 MHz, toluene-d₈): 147.0 ppm (99%).

Example 3: Synthesis of (XIII) Reaction of tert-butyl(3,3′-di-tert-butyl-2′-((dichlorophosphino)oxy)-5,5′-dimethoxy-[1,1′-biphenyl]-2-yl)carbonatewith 2,2′-biphenol

In a 250 ml Schlenk flask which had been repeatedly evacuated and filledwith inert gas, 10.5 g (0.019 mol) of tert-butyl(3,3′-di-tert-butyl-2′-((dichlorophosphino)oxy)-5,5′-dimethoxy-[1,1′-biphenyl]-2-yl)carbonatewere dissolved in 50 ml of degassed acetonitrile while stirring.

In a second Schlenk flask (250 ml) which had been repeatedly evacuatedand filled with inert gas, 3.6 g (0.019 mol) of 2,2′-biphenol weredissolved in 40 ml of degassed acetonitrile and 6.3 ml (0.045 mol) ofdried triethylamine while stirring. Subsequently, the chlorophosphitemixture was slowly added dropwise at room temperature to thebiphenol/triethylamine solution, and the mixture was stirred at roomtemperature overnight. The resultant solids were filtered and dried. Thetarget product (XIII) was obtained as a white solid (11.5 g, 90%). ³¹PNMR (202.4 MHz, toluene-d₈): 146.2 ppm (100%).

Example 4: Synthesis of (XIV)

Reaction of tert-butyl(3,3′-di-tert-butyl-2′-((dichlorophosphino)oxy)-5,5′-dimethoxy-[1,1′-biphenyl]-2-yl)carbonatewith 3,3,5,5-tetra-tert-butylbiphenol

In a 250 ml Schlenk flask which had been repeatedly evacuated and filledwith inert gas, 7.0 g (0.0125 mol) of tert-butyl(3,3′-di-tert-butyl-2′-((dichlorophosphino)oxy)-5,5′-dimethoxy-[1,1′-biphenyl]-2-yl)carbonatewere dissolved in 100 ml of dried acetonitrile.

In a second Schlenk flask (100 ml) which had been repeatedly evacuatedand filled with inert gas, 5.1 g (0.0125 mol) of3,3′,5,5′-tetra-tert-butylbiphenol were dissolved in 60 ml of driedacetonitrile and 4.2 ml (0.03 mol) of dried triethylamine whilestirring. Subsequently, the biphenol-triethylamine solution was slowlyadded dropwise at room temperature to the chlorophosphite solution andthe mixture was stirred overnight. A portion of the solvent was removedunder reduced pressure. The precipitated solids were filtered off anddried. The target product (XIV) was obtained as a white solid (10.2 g,91%). ³¹P NMR (202.4 MHz, toluene-d₈): 142.7 ppm (100%).

Example 5: Synthesis of (XV) Reaction of tert-butyl(3,3′-di-tert-butyl-2′-((dichlorophosphino)oxy)-5,5′-dimethoxy-[1,1′-biphenyl]-2-yl)carbonatewith 3,3-di-tert-butyl-5,5-dimethoxybiphenol

In a 250 ml Schlenk flask which had been repeatedly evacuated and filledwith inert gas, 7 g (0.0125 mol) of tert-butyl(3,3′-di-tert-butyl-2′-((dichlorophosphino)oxy)-5,5′-dimethoxy-[1,1′-biphenyl]-2-yl)carbonatewere dissolved in 100 ml of dried acetonitrile.

In a second Schlenk flask (100 ml) which had been repeatedly evacuatedand filled with inert gas, 4.5 g (0.0125 mol) of3,3-di-tert-butyl-5,5-dimethoxybiphenol were dissolved in 60 ml of driedacetonitrile and 4.2 ml (0.03 mol) of degassed triethylamine.Subsequently, the biphenol-triethylamine solution was slowly addeddropwise at 40° C. to the chlorophosphite solution, and the reactionmixture was heated to 80° C. and stirred at this temperature for 6 h.This was followed by hot filtration.

A portion of the solvent was removed under reduced pressure. Theprecipitated solids were filtered off and dried. The target product (XV)was obtained as a white solid (10.5 g, 96%). ³¹P NMR (202.4 MHz,toluene-d₈): 140.9 ppm (95.2%) and further impurities (furtherimpurities=P—H compounds, oxide compounds, as yet incompletely convertedchlorophosphite).

Example 6: Synthesis of (XVI) Reaction of tert-butyl(3,3′-di-tert-butyl-2′-((dichlorophosphino)oxy)-5,5′-dimethoxy-[1,1′-biphenyl]-2-yl)carbonatewith 2,4-dimethylphenol

In a 500 ml Schlenk flask which had been repeatedly evacuated and filledwith inert gas, 6.8 g (0.012 mol) of tert-butyl(3,3′-di-tert-butyl-2′-((dichlorophosphino)oxy)-5,5′-dimethoxy-[1,1′-biphenyl]-2-yl)carbonatewere dissolved in 100 ml of dried acetonitrile.

In a second Schlenk flask (250 ml) which had been repeatedly evacuatedand filled with inert gas, 6 g (6 ml; 0.048 mol) of 2,4-dimethylphenolwere dissolved in 100 ml of dried acetonitrile and 5 g (7 ml; 0.059 mol)of degassed triethylamine. Subsequently, the biphenol-triethylaminesolution was slowly added dropwise at room temperature to thechlorophosphite solution and the mixture was stirred at room temperatureovernight and cooled in an ice bath the next morning.

A portion of the solvent was removed under reduced pressure. This formeda slime-like solution which solidified after prolonged drying. Thetarget product (XVI) was obtained as a white solid (11.8 g, 62%). ³¹PNMR (202.4 MHz, toluene-d₈): 139.1 ppm (92.8%) and further impurities(further impurities=P—H compounds, oxide compounds, as yet incompletelyconverted chlorophosphite).

Example 7: Synthesis of bis(2,4-di-tert-butyl-6-methylphenyl)ethylphosphate

A 250 ml Schlenk flask with magnetic stirrer, attachment, droppingfunnel and reflux condenser was initially charged with 22.5 g (0.1 mol)of 2,4-di-tert-butyl-6-methylphenol (4,6-di-tert-butyl-ortho-cresol),and heated to 55° C. in order to melt the phenol. 0.13 ml (0.0015 mol)of dried degassed dimethylformamide was added to the melt. Subsequently,5.7 ml (0.065 mol) of phosphorus trichloride were added dropwise within2 hours. After the addition had ended, the reaction mixture was heatedto 140° C. within 3 hours and stirred at this temperature for 1 hour.Then the mixture was stirred at 130° C. under reduced pressure for 1hour. Thereafter, the clear yellow-orange melt obtained(=bis(2,4-di-tert-butyl-6-methyl) phosphochloridite) was cooled down to80° C. overnight and diluted with 75 ml of degassed petroleum (80-110°C.). After the solution had been cooled down to −5° C., 9.1 ml (0.0665mol) of degassed triethylamine were added within 15 minutes.Subsequently, within 2 hours, 4.4 ml (0.075 mol) of dried and degassedethanol were added dropwise, in the course of which the temperature didnot rise above 5° C. This mixture was warmed gradually to roomtemperature overnight while stirring.

The next morning, the precipitated triethylamine hydrochloride wasfiltered off and the filtrate was concentrated under reduced pressure.This gave a white residue which was recrystallized in 60 ml of degassedethanol. The product was thus obtained in a yield of 73.9% (19.03 g) asa white solid in 98% purity by LC-MS.

Chlorine Reduction Example 8: Chlorine Reduction of (XI)

a) toluene-DMAB/Acetonitrile-DMAB

In a 500 ml Schlenk flask which had been repeatedly evacuated and filledwith inert gas, 10 g of crude ligand (XI) having an initial chlorinelevel of 5.7% by weight were heated to 105° C. in 40 ml of degassedtoluene and 10 ml of N,N′-dimethylaminobutane with stirring.

A second 500 ml Schlenk flask which had been repeatedly evacuated andfilled with inert gas was initially charged with 90 ml of degassedacetonitrile and 10 ml of N,N′-dimethylaminobutane, while stirring.Thereafter, the ligand/toluene/amine solution was added dropwise at roomtemperature to the acetonitrile-amine solution while stirring within acouple of minutes. In order to hold back the insoluble solid fraction,dropwise addition took place through a frit.

After the clear solution had been stirred for 12 hours, the solvent wasremoved under reduced pressure. Thereafter, the resulting solid wasadmixed with 40 ml of degassed acetonitrile and stirred at roomtemperature for 12 hours. The mixture was subsequently filtered anddried. The product was obtained in 67% yield (5.9 g).

NMR result: 100% P 139.3 ppm (toluene-d8).

Result of duplicate Wickbold chlorine determination: 65/65 mg/kg (ppm)

For accuracy, the chlorine levels were analyzed in a duplicatedetermination.

b) Toluene-DMAB/Acetonitrile

In a 2 l Schlenk vessel which had been repeatedly evacuated and filledwith inert gas, 115.6 g of crude ligand (XI) having an initial chlorinelevel of 5.7% by weight were heated to 105° C. in 460 ml of degassedtoluene and 100 ml of N,N′-dimethylaminobutane, with stirring, andstirred at this temperature for about 10 minutes.

For further work-up, the mixture was cooled to room temperature andfiltered through a frit. The resulting filtrate was then concentrated todryness under reduced pressure. Thereafter, the solid obtained wasadmixed with 290 ml of degassed acetonitrile, stirred for 15 minutes at78° C., cooled to room temperature again and stirred at room temperatureovernight. In the morning, the solid was filtered off, rinsed with 50 mlof degassed acetonitrile, and dried. The product was obtained in 61.8%yield.

NMR result: 100% P 139.3 ppm (toluene-d8).

Result of duplicate Wickbold chlorine determination: 75/80 mg/kg (ppm)

c) Toluene-DMAB/Acetonitrile

In a 2 l Schlenk vessel which had been repeatedly evacuated and filledwith inert gas, 189.6 g of crude ligand (XI) having an initial chlorinelevel of 1.1% by weight were heated to 105° C. in 760 ml of degassedtoluene and 165 ml of N,N′-dimethylaminobutane, with stirring, andstirred at this temperature for about 10 minutes.

For further work-up, the mixture was cooled to room temperature andfiltered through a frit.

The resulting filtrate was then concentrated to dryness under reducedpressure, admixed with 475 ml of degassed acetonitrile, stirred at 75°C. for 15 minutes and then cooled back down to room temperature withstirring overnight. In the morning, the solid was filtered off, rinsedwith 50 ml of degassed acetonitrile, and dried.

The product was obtained in 86% yield (160 g).

NMR result: 100% P 139.3 ppm (toluene-d8).

Chlorine result according to Wickbold: <10 mg/kg (ppm)

d) Work-Up Using o-Xylene/Methanol/Triethanolamine

In a 100 ml Schlenk flask which had been repeatedly evacuated and filledwith inert gas, 10.06 g of (XI) having an initial chlorine level of 1.1%by weight were weighed out and admixed with 45 ml of degassed o-xylene.This suspension was heated to 102° C. and left with stirring for 20minutes. During this time, the major fraction dissolved. Only a fewparticles were insoluble. Subsequently, the slightly turbid solution wassubjected to hot filtration, and the clear filtrate was concentrated todryness under reduced pressure at room temperature.

The next morning, 150 ml of degassed methanol and 15 ml of degassedtriethanolamine were added to the solid residue from the concentratedfiltrate, and stirring was carried out for 3 hours. This gave a whitesuspension. The solid was subsequently isolated by filtration and dried.

The product was obtained in 87% yield (8.65 g).

NMR result: 99.8% P 139.3 ppm (toluene-d8).

Chlorine result according to Wickbold: 20 mg/kg (ppm)

e) Work-Up Using Toluene/Methanol/Triethanolamine

In a 100 ml Schlenk flask which had been repeatedly evacuated and filledwith inert gas, 10.06 g of (XI) having an initial chlorine level of 1.1%by weight were weighed out and admixed with 45 ml of degassed toluene.This suspension was heated to 102° C. and left with stirring for 20minutes.

During this time, the major fraction dissolved. Only a few particleswere insoluble. Subsequently, the slightly turbid solution was subjectedto hot filtration, and the clear filtrate was concentrated to drynessunder reduced pressure at room temperature.

The next morning, 150 ml of degassed methanol and 15 ml of degassedtriethanolamine were added to the solid residue from the concentratedfiltrate, and stirring was carried out for 3 hours.

This gave a white suspension. The solid was subsequently isolated byfiltration and dried.

The product was obtained in 98% yield (9.8 g).

NMR result: 100% P 139.3 ppm (toluene-d8).

Chlorine result according to Wickbold: 120 mg/kg (ppm)

Example 9: Chlorine Reduction of (XV) a) Work-Up Using DegassedMethanol+5% Degassed DMAB at 0° C.

The crude ligand (XV) with an initial chlorine level of 1.3% by weightwas dissolved in 80 ml of dried toluene. The solution was thenintroduced slowly dropwise and with stirring into a 1 l Schlenk flaskfilled with 600 ml of degassed methanol and 30 ml of degasseddimethylaminobutane (DMAB), and stirred for 1 h. A white solid wasobtained. The mixture was then cooled to 0° C. and stirred for a further2 h. The solid obtained was subjected to cold filtration, rinsed oncewith 60 ml of cold, degassed methanol, and dried.

Result of duplicate Wickbold chlorine determination: <10/<10 mg/kg (ppm)Yield: 28.6 g corresponding to 55%.

b) Work-Up Using Degassed Methanol+5% Degassed Water+5% Degassed DMAB at0° C.

The crude ligand (XV) with an initial chlorine level of 1.3% by weightwas dissolved in 80 ml of dried toluene. The solution was thenintroduced slowly dropwise and with stirring into a 11 Schlenk vesselfilled with 600 ml of degassed methanol, 30 ml of degassed DI water and30 ml of degassed DMAB, and stirred for 1 h. This gave a white solid.The mixture was then cooled to 0° C. and stirred for a further 2 h. Thesolid obtained was subjected to cold filtration, rinsed once with 60 mlof cold, degassed methanol, and dried.

Result of duplicate Wickbold chlorine determination: 90/100 mg/kg (ppm)

Yield: 36.36 g

c) Work-Up Using Degassed Methanol+5% Degassed Water+2.5% Degassed DMABat 0° C.

The crude ligand (XV) with an initial chlorine level of 1.3% by weightwas dissolved in 80 ml of dried toluene. The solution was thenintroduced slowly dropwise and with stirring into a 1 l Schlenk vesselfilled with 600 ml of degassed methanol, 30 ml of degassed DI water and15 ml of degassed DMAB, and stirred for 1 h. This gave a white solid.The mixture was then cooled to 0° C. and stirred for a further 2 h. Thesolid obtained was subjected to cold filtration, rinsed once with 60 mlof cold, degassed methanol, and dried.

Result of duplicate Wickbold chlorine determination: 70/80 mg/kg (ppm)

Yield: 36.2 g corresponding to 70.5%.

d) Work-Up Using Degassed Methanol+7.5% Degassed Water+2.5% DegassedDMAB at 0° C.

The crude ligand (XV) with an initial chlorine level of 1.3% by weightwas dissolved in 80 ml of dried toluene. The solution was thenintroduced slowly dropwise and with stirring into a 1 l Schlenk vesselfilled with 600 ml of degassed methanol, 45 ml of degassed DI water and15 ml of degassed DMAB, and stirred for 1 h. This gave a white solid.The mixture was then cooled to 0° C. and stirred for a further 2 h. Thesolid obtained was subjected to cold filtration, rinsed once with 60 mlof cold, degassed methanol, and dried.

Result of duplicate Wickbold chlorine determination: 85/90 mg/kg (ppm)

Yield: 37.5 g corresponding to 73%.

e) Work-Up Using Degassed Methanol+7.5% Degassed Water+5% Degassed DMABat 0° C.

The crude ligand (XV) with an initial chlorine level of 1.3% by weightwas dissolved in 80 ml of dried toluene. The solution was thenintroduced slowly dropwise and with stirring into a 1 l Schlenk vesselfilled with 600 ml of degassed methanol, 45 ml of degassed DI water and30 ml of degassed DMAB, and stirred for 1 h. This gave a white solid.The mixture was then cooled to 0° C. and stirred for a further 2 h. Thesolid obtained was subjected to cold filtration, rinsed once with 60 mlof cold, degassed methanol, and dried.

Result of duplicate Wickbold chlorine determination: 80/80 mg/kg (ppm)

Yield: 38.1 g corresponding to 74%.

f) Work-Up Using Degassed Methanol+5% Degassed Water+5% Degassed DMAB at0° C.

The crude ligand (XV) with an initial chlorine level of 1.3% by weightwas dissolved in 80 ml of dried toluene. The solution was thenintroduced slowly dropwise and with stirring into a 1 l Schlenk vesselfilled with 500 ml of degassed methanol, 25 ml of degassed DI water and25 ml of degassed DMAB, and stirred for 1 h. This gave a white solid.The mixture was then cooled to 0° C. and stirred for a further 2 h. Thesolid obtained was subjected to cold filtration, rinsed once with 60 mlof cold, degassed methanol, and dried.

Result of duplicate Wickbold chlorine determination: 20/20 mg/kg (ppm)

Yield: 36.1 g corresponding to 70.3%.

g) Work-Up Using Toluene/Ethanol N,N′-Dimethylaminobutane

The crude ligand (XV) with an initial chlorine level of 1.3% by weightwas dissolved in 80 ml of dried toluene. The solution was then addedslowly with stirring to a 250 ml Schlenk flask containing 80 ml ofdegassed ethanol and 4 ml of degassed N,N′-dimethylaminobutane (5%) at0° C. The mixture was stirred at 0° C. for 4 hours. No precipitations ofproduct were detectable in the Schlenk flask. Here again, therefore,concentration to dryness was carried out, the solid was then pulverized,and the solid was admixed, with stirring, initially with 80 ml ofdegassed ethanol and with 4 ml of degassed N,N′-dimethylaminobutane. Themixture was first of all stirred at room temperature shortly, with thesolid going into solution. The initial precipitates were visible againafter around 3 minutes. The mixture was subsequently cooled to 0° C. andstirred for 3 h. The solid was then isolated by filtration, rinsed with10 ml of cold, degassed ethanol, and dried.

Result of duplicate Wickbold chlorine determination: 190/200 mg/kg (ppm)

Yield: 16.7 g corresponding to 64.41%.

TABLE 1 Chlorine levels Chlorine level, average value 1st solvent 1stbase 2nd solvent 2nd base [ppm] 8a) toluene DMAB acetonitrile DMAB 658b) toluene DMAB acetonitrile 77.5 8c) toluene DMAB acetonitrile <10 8d)o-xylene methanol triethanolamine <20 8e) toluene methanoltriethanolamine 120 9a) toluene methanol DMAB <10 9b) toluenemethanol/H₂O DMAB 95 9c) toluene methanol/H₂O DMAB 75 9d) toluenemethanol/H₂O DMAB 87.5 9e) toluene methanol/H₂O DMAB 80 9f) toluenemethanol/H₂O DMAB 20 9g) toluene ethanol DMAB 195 DMAB:dimethylaminobutane

The examples above show on the one hand that by virtue of the process ofthe invention, the chlorine content of organomonophosphites can bereduced significantly, for example from an initial chlorine contentof >50 000 ppm (as in examples 8a) and 8b)) to a final content of <200ppm, or from an initial chlorine content of 11 000 ppm (example 8c)) or13 000 ppm (examples 9a) to 9f)) to a final content of <200 ppm.

The examples also show that even water-containing solvents (as inexamples 9b) to 9f)) can be used and that there is no absolute need forthe organic solvents to be dried. In the case of phosphites, water canlead to decompositions and hence to yield losses. This is not observedin the process of the invention, owing to the addition ofdimethylaminobutane or triethanolamine. This means that it is possibleto dispense with an inconvenient and costly drying of the solvents.

1. A process for reducing the chlorine content in an organomonophosphiteof one of the general formulae I, II, III, IV, V, VI, VII, VIII, IX andX:

where the radicals R¹, R², R³, R⁴, R⁵, R⁶, R⁷, R⁸, R²¹, R²², R²³, R²⁴,R²⁵, R³¹, R³², R³³, R³⁴, R³⁵, R⁴¹, R⁴², R⁴³, R⁴⁴ and R⁴⁵ are selectedeach independently from: —H, —(C₁-C₁₂)-alkyl, —O—(C₁-C₁₂)-alkyl,—O—(C₆-C₂₀)-aryl, —(C₆-C₂₀)-aryl. and R¹⁰ is —(C₁-C₁₂)-alkyl; and T isselected from: —CH₃, —CF₃, —CH₂C₆H₅; and Q is selected from:—(C₁-C₁₂)-alkyl-, —C(CH₃)₃; and V is selected from: —CH₂CH₂COCH₃,—C(CH₃)₃, —C₆H₅; and W is selected from: -Me, —CH₂CH₃, —CH₂CH₂CH₃,—CH₂-cyclo-C₃H₅, —CH(CH₃)₂, -cyclo-C₆H₁₁, —C(CH₃)₃, —CH₂C₆H₅,—CH₂C₆H₃-2,4-(CH₃)₂; and X and Y are each independently selected from:—(C₁-C₁₂)-alkyl, —(C₆-C₂₀)-aryl, —(C₆-C₂₀)-aryl-(C₁-C₁₂)-alkyl,—(C₁-C₁₂)-alkyl-(C₆-C₂₀)-aryl; and Z is selected from: —(C₆-C₂₀)-aryl-,—(C₆-C₂₀)-aryl-(C₆-C₂₀)-aryl-; and the alkyl, cycloalkyl, and arylgroups mentioned may be substituted; comprising the process steps of: a)partly or fully dissolving the organomonophosphite in a first solutioncomprising a first solvent selected from aromatics, alcohols, acetone,ethyl acetate, acetonitrile and ether; b) introducing the first solutioninto a second solution comprising a second solvent selected fromaromatics, C₅-C₁₀-alkanes, alcohols, acetone, ethyl acetate,acetonitrile, ether, water, where at least one of the two solutionscomprises dimethylaminobutane or triethylamine or triethanolamine; c)precipitating the purified organomonophosphite.
 2. The process accordingto claim 1, wherein the first solvent is selected from: ethyl acetate,anisole, ortho-xylene, toluene, acetone, methanol, ethanol, propanol,isopropanol, acetonitrile.
 3. The process according to claim 1, whereinthe first solvent is toluene.
 4. The process according to claim 1,wherein the second solvent is selected from: ethyl acetate, anisole,ortho-xylene, toluene, acetone, methanol, ethanol, propanol,isopropanol, acetonitrile, tetrahydrofuran, diethyl ether, glycol,C₅-C₁₀-alkanes.
 5. The process according to claim 1, wherein the secondsolvent is acetonitrile or methanol.
 6. The process according to claim1, wherein the second solution comprises a third solvent.
 7. The processaccording to claim 6, wherein the third solvent is water.
 8. The processaccording to claim 1, wherein the organomonophosphite is dissolved fullyin the first solution in process step a).
 9. The process according toclaim 1, wherein the purified organomonophosphite has a chlorine contentof <1000 ppm.
 10. The process according to claim 1, wherein the purifiedorganomonophosphite has a chlorine content of <200 ppm.
 11. The processaccording to claim 1, wherein, following the introduction of the firstsolution into the second solution, the temperature is lowered to −20 to+10° C. in order to increase the degree of precipitation.
 12. Theprocess according to claim 1, wherein the organomonophosphite has one ofthe general formulae I, II, III and IV:


13. The process according to claim 1, wherein R¹, R², R³, R⁴, R⁵, R⁶,R⁷, R⁸ are each independently selected from: —H, —(C₁-C₁₂)-alkyl,—O—(C₁-C₁₂)-alkyl, —O—(C₆-C₂₀)-aryl, —(C₆-C₂₀)-aryl; and W is —CH₃; andQ is —C(CH₃)₃.
 14. The process according to claim 1, where Z is:

and where R¹¹, R¹², R¹³, R¹⁴, R¹⁵, R¹⁶, R¹⁷, R¹⁸ are each independentlyselected from: —H, —(C₁-C₁₂)-alkyl, —O—(C₁-C₁₂)-alkyl, —O—(C₆-C₂₀)-aryl,—(C₆-C₂₀)-aryl, -halogen, —COO—(C₁-C₁₂)-alkyl, —CONH—(C₁-C₁₂)-alkyl,—(C₆-C₂₀)-aryl-CON[(C₁-C₁₂)-alkyl]₂, —CO—(C₁-C₁₂)-alkyl,—CO—(C₆-C₂₀)-aryl, —COOH, —OH, —SO₃H, —SO₃Na, —NO₂, —CN, —NH₂,—N[C₁-C₁₂)-alkyl]₂.
 15. (canceled)